Oil-containing, hydrophilic-walled microcapsules, such as those having hardened gelatin walls and core-material of any of a multitude of oils, have long been known and used in the pressure-sensitive record material art. Such microcapsules also have many other uses as containers for various materials such as odorants, medicaments, and pesticides. Because hydrophilic, polymeric film-forming materials are water-soluble or water-swellable even after hardening by cross-linking, the use of aqueous solutions as the corematerial of hydrophilic-walled microcapsules has been precluded. Great effort has been expended, with varying degrees of success, to contain water and water solutions in microcapsules since the early beginnings of encapsulation technology. Aqueous liquids have been encapsulated in hydrophobic-walled microcapsules by expensive processes which make use of expensive materials and give a product with severely limited shelf life. Hydrophilic-walled microcapsules having oily contents have been subjected to through-the-wall exchange procedures whereby the oily contents are replaced by lyophilic liquids which may have oil-soluble and/or water-soluble materials dissolved therein. Such a total replacement procedure is disclosed and claimed in U.S. Pat. No. 3,516,943 which issued June 23, 1970 on the application of Carl Brynko and Gerald M. Olderman. This procedure, although effective in making microcapsules having water-soluble materials in the core, involves the replacement of the original oily contents of the capsules with non-oily (water-soluble) liquids that are more difficult to retain than oils over extended periods of time. Various further improvements have dealt with this problem of prolonged retention as by the addition of an outer hydrophobic wall to preformed microcapsules such as the Brynko-Olderman microcapsules discussed above. Such improvement procedures have met with some success but are generally too expensive for widespread use.